Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Additional Information (Detail)

v3.10.0.1
Fair Value Measurements - Additional Information (Detail) - USD ($)
Dec. 31, 2018
Dec. 31, 2017
Minimum    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Unpaid principal balance of Non-accrual Non-PCI loans reviewed individually for amount of impairment $ 250,000  
Maximum    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Unpaid principal balance of Non-accrual Non-PCI loans reviewed collectively for amount of impairment 250,000  
Impaired loans | Real estate loans | Non-recurring Basis    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Impaired loans 3,500,000 $ 6,700,000
Impaired loans | Commercial and industrial loans | Non-recurring Basis    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Impaired loans $ 1,700,000 $ 1,700,000